Hi, it looks like your hotel is located in Mestre, the industrial part of greater Venice. Take the train onto the island grouping of Venice (shaped like a fish). Be ready for the vaporetto boat buses to be very busy. (Buy your extra tickets at the same time.) Yes, I love Venice and purposely wandering is a wonderful “activity”. Reserve a ticket now to go into St. Marks Cathedral. Leave your backpack, etc. in your hotel room; just wear your crossbody purse & moneybelt under your clothes.
Burano is my favorite extra island to visit because of all of the colorful buildings. Photography is my souvenirs. You may or may not want to take the time to go there. Personally, I’d skip Murano with your short time in Venice.
Suso gelato is my favorite in Venice, and their Manet flavor is amazing!
Of all of the things to do in Venice, one of my favorites is to spend the last evening at an outdoor table at the Florian. Not during the day & not inside. For the cost of one beverage & payment for the small orchestra playing, you can savor the atmosphere of Venice after the day tourists have left with lovely music playing, watch the colors change in the piazza with the setting sun, and see the piazza illuminated by the lights from the buildings - all from a relaxed, unrushed spot at the table. Magical!